The present invention relates to a plug which is almost free from short-circuiting between its power supply contacts and signal contacts by foreign objects, and a socket into which the plug is put.
FIG. 1 shows a conventional plug, in which contacts 12 are held by and project out from a body 11 of an insulating material fixedly housed in a cylindrical metallic shield cover 13. The contacts 12 extend in the cylindrical shield cover 13 to the vicinity of its forward end.
FIGS. 2 and 3 show a conventional socket, in which contacts 18 are housed in contact housing holes 17 made in a columnar portion 16 inside a cylindrical groove 15 cut in the front of a socket body 14 of an insulating material. The columnar portion 16 has cut in its peripheral surface a main positioning groove 19a and sub positioning grooves 19b and 19c extending lengthwise thereof. In the traditional plug which is put into such a socket, the contacts 12 have their forward end exposed in the vicinity of the forward end of the shield cover 13. In order for the plug and the socket to connect therethrough the power supply line as well, it is necessary to provide power supply contacts as well as the signal contacts 12 in the plug body 11 and to house the corresponding power supply contacts in contact housing holes made in the columnar portion 16 of the socket body 14. In the plug of such a construction, however, there is a possibility that when a conductive foreign object happens to enter into the cylindrical shield cover 13 of the plug, even though slightly, the contacts are shorted by the foreign object. In particular, shorting between the signal contact 12 and the power supply contact is very likely to destroy signal circuits of electronic equipment connected to each of the plug and the socket.